Abstract Details

files Add files

Oscillating Field Current Drive on MST

Author: Karsten J. McCollam
Requested Type: Poster Only
Submitted: 2006-12-18 16:45:04

Co-authors: A.Almagri, J.Anderson, A.Blair, D. Brower, D.Craig, D.Den Hartog, B. Deng, W. Ding, F.Ebrahimi, G.Fiksel, S.Gangadhara, R.O'Connell, S.Prager, J.Sarff, D.Stone

Contact Info:
University of Wisconsin - Madison
1150 University Ave
Madison, WI   53706

Abstract Text:
Oscillating field current drive (OFCD) is a proposed method of efficient, steady-state toroidal plasma current sustainment that uses AC poloidal and toroidal inductive loop voltages, without magnetizing poloidal flux accumulation. In MST, OFCD is added to the standard transient induction of the RFP in order to add about 10% to the total plasma current, with an Ohmic current drive efficiency. In these experiments OFCD modulates the amplitudes of magnetic fluctuations, but need not cause a significant increase in global mean amplitude, and some individual mode amplitudes are slightly reduced. The evolution of the modulated current and pressure profiles, including a 50% modulation in central electron pressure, is obtained using internal magnetic field and electron density and temperature data, from which resistivity and confinement characteristics are also inferred. The mean electron temperature profile is maintained at the standard level and may actually increase slightly. The added current is maximal for positive, but not maximal, helicity injection, which is likely due in part to OFCD's modulating effect on magnetic fluctuations, which are smallest at the maximal added current. OFCD also modulates the ion temperature and anomalous ion heating. The experimental results are generally consistent with both 1D relaxed-state modeling and detailed 3D resistive-MHD computation, which has also shown that OFCD is capable in principle of fully sustaining the RFP in a steady state. An upgraded OFCD system for MST is in construction and nearly ready for plasma experiments with more applied power and longer pulses. This work is supported by the US DOE.

Characterization: A3,E3

Please place next to other MST and/or RFP posters if in same session and if this is consistent with your plan. Thanks.

University of Maryland

Innovative Confinement Concepts Workshop
February 12-14, 2007
College Park, Maryland

ICC 2007 UM logo